Telephone-exchange system



July 15 1924. 1,501,676 5. LUNQELL ET AL TELEPHONE EXCHANGE SYSTEM JJJJJJJ.

Filed July 1, 1920 '7 Sheets-Sheet 1 //71/e/7fars: Awe/1 E Lande/A James J Wyn/7e.

July 15 1924.

A. E. LUNDELL ET AL TELEPHONE EXCHANGE SYSTEM Filed July 1, 1920 7 Sheets-Sheet 2 July '15 1924. 1,501,676

A. LUNDELL ET AL TELEPHONE EXCHANGE SYSTEM 1920 V 7 Sheets-Sheet 4 A. E. LUNDELL ET AL I TELEPHONE EXCHANGE SYSTEM Filed July 1,

July 15 I924.

A/ben f. Lfl/vdel/ James J Wyn/1e. by W /l// 1,501,676 A. E. LUNDELL ET A...

TELEPHONE EXCHANGE SYSTEM Filed July 1, 1920 7 Sheets-Sheet 5' Mfi m July 15 1924.

Awe/1E. Luna e- James J y y ,2; I 4

July 15., 1924.

A. E LUNDELL ET AL TELEPHONE EXCHANGE SYSTEM Filed July 1, 1920 7 Sheets-Sheet 6 July 15 1924.

- 1,501,676 A. E. LUNDELL ET AL TELEPHONE EXCHANGE SYSTEM Filed July 1, 1920 7 Sheets-$h eet 7 f my Patented July 15, 1924.

UNITED STATES PATENT OFFICE.

ALBEN E. LUNIDELL, OF CHICAGO, ILLINOIS. AND JAMES J. WYNNE, OF ROSELL'E PARK, NEW JERSEY, ASSIGNOR-S TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed July 1,

T 0 all whom it may concern.

Be it known that we, ALBEN E. LUNDELL and JAMES J. \VYNNE, citizens of the United States, residing at Chicago, in the county of Cook and State of Illinois, and at Roselle Park, in the county of Union and State of New Jersey, respectively, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and correct description.

This invention relates to automatic telephone exchange systems and more particularly to systems employing switches of the power driven type and in which the switches are controlled by means of a sender located at the central oflice.

It is the object of this invention to provide an intermediate registering device of such a nature that a change of routing may be made by simply altering the connections at a common cross connecting board instead of being obliged to alter the wiring of each sender involved.

It is a further object of the invention to provide suitable mechanism and circuits for accomplishing the transfer of registrations from one set of registers to another in a novel manner.

An additional object of the invention is the provision of a quick acting registering device which may be positioned under the joint control of a plurality of. primary registering devices. In the present disclosure the primary registering devices have been shown as operator controlled keys, but it is to he understood that such keys show merely one embodiment of the invention and that other forms of primary registering devices such as registers positioned under the con-'- trol of an impulse transmitter may be utilized without departing from the spirit of the invention.

A feature of the invention is the use of a multi-position switch which is positioned in accordance with the settings of a plurality of registering devices.

A further feature of the invention resides in the provision of means for actuating a set of register relays under the control of an impulse sending device in accordance with the setting of the aforesaid rnultiposi- 1920. Serial No. 393,377.

tion switch. The impulse sending device is preferably common to all the register relays of the exchange.

Other features of the invention result from the arrangement of the controlling circuits for said switch and register relays, and will be clearly apparent from the detailed description which follows.

The invention has been shown applied to a semionechanical system of the type shown in Patent No. 1,345,016, issued June 29, 1920. to A. E. Lundell and F. A. Stearn. The invention is, however, obviously capable of a wide range of usage'and is therefore to be limited only by the appended claims.

In the drawing the various figures show so much of a telephone exchange system as is necesary to an understanding of the invention. Fig. 1 shows a link circuit at a cordless operators position and includes a dis rict selector switch and controlling cin cuits therefor. Fig. 2 shows a link circuit to be used in associating an idle sender with the cord circuit which has been taken for use and includes the controlling circuits for cord tinder switch and a sender selector switch. Fig. 3 shows a portion of the con trol. circuit for setting the sender register relays. Fig. 4 shows a set of counting relays for controlling the operation of the various selector switches of the system together with a sequence switch to control the progress of. operations in the sender. Fig. 5 shows a group of register relays and a class sequence switch and its circuits. 6 shows a portion of an operators key set together with the multiposition switch which takes up a registration in accordance with which keys ha e been depressed. This figure also shows an impulse generating device to be used in setting the register relays of 7 in accordance with the position assumed by the multiposition switch. Fig. 7 are shown the circuits of various register relays together with a controlling sequence switch which not only controls the multiposition switch of Fig.6 but also controls the progress of impulse transmission in transferring the setting of the relays shown in Fig. 7 to'the relays shown in Fig. 5. v

'- A general description of the system will first be given in order that the detailed description which follows may be more readily understood.

The general operation of the system is substantially similar to that described in the above mentioned Patent to A. E. Lundell and F. A. Stearn, No. 1,345,016. The operator controlling the district switch shown in Fig. 1 assigns the trunkshown in such figure, after receiving instructions from an A operator (not shown) over an order wire (not shown). then plugs into such trunk causing the operation of signals which informv the cordless operator. as she will be termed hereafter, that a call is awaiting extension. The cord less operator then depresses an assignment key. whereupon. the link circuit shown in Fig; 2 is put into operation. In practice there would be a number of these link circuits under the control of an allotter, but for the sake of simplicity only one link circuit has been shown. The link circuit is provided at each end with a hunting switch. The cordfindeir at one end hunts for the district circuit atwhich the assignment key has been depressed. while the sender selector on the other end of such link. hunts for an idle sender.

The cordless operator is proi' ided with a set of office keys and with a set of numerical keys. The numerical keys correspond to those described in the above mentioned ap-' plication and are not shown in the present application in order to avoid needlesss coinplication. The operatoi."'s office key set comiprises two rows of keys. therev being one set of vertical. keys and another set of horizon tal keys. Assuming that there are ten .hori Zontal keys and twenty vertical keys it is obvious that by using these keys on a coordinate basis two hundred combinations may be obtained. The arrangement of these keys on the key board is shown and described in Patent No. 1.369.003, issued February 22,

to V. G. Blauvelt.

After the operator has depressed the assignment key she will depress the proper office kevs and the proper nninerioal keys. The multiposition switch shown in Fig. 6. which will hereafter be termed a translator switch. is then put into operation to assume a position determined by the particular office 1- depressed in both the horizontal and the vertical row. During the hunting movement of the translator switch. the registration set up on the ni'imer'ical keys is transferred to the sender re ister relays (not shown) in a manner substantially the Saiii as in the aforementioned Liiride-ll-Stzirfi patent.

After the translator switch has been position'ed, an impulse generating machine comprising a plurality of drums which may be variably wired to the terminals enqa ed by the translator switch brushes. operates to The A operator energize the register relays of Fig. 7 in vari able combinations. The impulse generating machine is preferably connected to the terminals of the translator switch by means of a distributing frame so that changes in routing may be conveniently accomplished. The translator switch may then be restored and the registration is then transferred from the relays shown in Fig. 7 to the sender register relays of Fig. 5.

After the registration has been set up on the relays of Fig. the operation of the system is substantially similar to that described in the previously mentioned Patent No. 1.- 345.016 to A. E. Lundell and F. A. Stea rn.

The drums on the impulse generating. ma chine or inripulser as it may be termed. are mounted on the same shaft and are in con; tinuous rotation. In order that a better understanding of the sequence of events during a rotation of the impulser may he had the drums have been developed into a plane surface. the rectangles and squares on this surface representing points at which grounded battery is supplied to any brush which is in engagement with such segment. The direction of rotation of the drums is assumed to be in the direction of the arrow as shown in Fig. 6.

The advantage arising from the use of the translator switch is readily apparent even from the above general (lQSCliptlOll. It is obvious that. each of the translator switches maybe made to serve a portion of a multiple contact bank. which may be of the wellknm'n type ordinarily used in connection with the type of switch chosen for use as a translator which will be described herein aft-er. Therefore. any time that it is desirable to change the routing of a call, the only connections which must be changed are those extending from one set of multiple terminals to the brushes of the impulscr. and the proper change will then be. automatically transferred to the sender register relays at the proper time.

It is, of course. obvious that the translator switches used by the various operators in the exchange ma all have access to a multipled portion ofthe contact bank.

If a number of sections of nniltiple con tact banks are userh the terminals of such banks are brought to a distributing frame so that in order to change the connection from the impulse-r to any Contact. it is necessary to change only one connection.

The mechanical structure of tlie'translator switch is immaterial to the inventive idea. In the present embodiment of the invention the translator switch used is substantially similar to a switch described in Patent Xe. 1123,6596 issued to E. B. Craft and J. )T. Reynolds on January 5, 1915. In the pres ent case it. been assumed tlat each of the multiple brush sc r-mnpr...,; of

brushes. All of these brush sets are normally inoperative as is usual in a panel-type power driven selector switch and any one may be selected in the usual manner and rendered operative upon actuation of a trip rod which serves to release the siX brushes comprising the selected brush set into physical engagement with a section of the contact bank served by them. Each brush set is arranged to travel over a section of the. bank comprising forty terminals. A controlling commutator and associated commutator brushes are provided, this commutator being provided with segments suitably disposed to accomplish the control of the switch in accordance with the principles of the invention.

A detailed description of the operation of the system will now be given.

It will be asumed that a subscriber at an outlying manual ofiice wishes to originate a call. For the purpose of simplifying the description and drawings, it has been assumed that this call is to be extended to a desk located in the office containing the operators equipment. This means that no ofiice selectors need be employed since the call is local and there will be no utility for numerical designation. The numerical keys and registers and their controlling circuits have therefore been omitted.

Vhen the calling subscriber removes his receiver from the switchhook, he will. cause a signal to be lighted before an A operators position (not shown). The A operator will respond to this signal by plugging into the answering jack of the calling subscribers line and will then converse with him to ascertain the office and numerical designation of the call. The A operator will then converse with the cordless operator, one of whose circuits is shown in Fig. 1, by means of an order wire. The cordless operator will then assign a trunk and the A operator will plug into the outgoing end of such trunk. The substation of the calling subscriber and the A operators cord circuit together with the outgoing end of the trunk have not been disclosed. Suita-ble circuits for this purpose are, however. shown in Patent No. 1,34i2.823. issued June 8, 1920.. A. E. Lundell and E. H. Clark.

As soon as the A operator has plugged into the trunk terminating in Fig. 1 in conductors 101 and 102, a circuit is completed from grounded battery, sequence switch contact 103, right-hand winding of relay 104:. conductor 101, through the cord circuit of the A operator and a supervisory relay included therein, returning by way of conductor 102, left-hand winding of relay 104. sequence switch contact 105 to ground. Relay 104 is energized in this circuit and completes a circuit from ground ed battery, left-hand winding of relay 106,

sequence switch contact 10:, armature and contact of relay 104 to ground. Relay 106 is energized in this circuitand completes a circuit from grounded battery through lamp 108, left-hand contacts of sequence switch spring 109, inner right-hand armature and front contact of relay 106, righthand contact of sequence switch spring 110, outer right-hand armature and front contact of relay 106, lower contacts of sequence switch spring 111 to ground. The lamp 108 is lighted to inform the cordless operator that the A operator has plugged. into the trunk jack. She thereupon depresses a nonlocking assignment. key 112, thereby completing a circuit from grounded battery, power magnet of sequence switch 100, lower contact of sequence switch spring 113, left-' hand contacts of key 112, to ground, for moving this sequence switch out of position 1 and into position 2. As soon as sequence switch 100 leaves position 1, the circuit of relay 106 is broken and this relay deenergizes.

In position 2 of sequence switch 100, a circuit is completed from grounded battery. winding of relay 201, (Fig. 2), left-hand contacts of sequence switch spring 202, conductor 203, upper left-hand and lower righthand contacts of sequence switch spring 114, inner right hand armature and back contact of relay 106, upper contacts of sequence switch spring 100 to ground. Relay 201 is. energized in this circuit and completes a circuit from grounded battery, lefthand winding; of relay 204. upper contacts of sequence switch spring 205, outer righthand armature and front contact of relay 201 to ground. Relay 204 is energized in this circuit and completes a circuit from grounded battery. power magnet of sequence switch 200. upper right-hand contact of sequence switch spring 206. inner riejhthand armature and front contact of relay 204. to ground. for moving this sequence switch out of position 1 and into position 2.

In position 2 of sequence switch 200, a circuit is completed from grounded battery. winding of up-drive magnet 207, left-hand contacts of sequenceswitch spring 205, outer right-hand armature and front contact of relay 201 to ground. Under the control of magnet 207, the cord finder brush shaft is elevated in, search of the terminal set corresponding to the district switch circuit at which the associated assignment. key has been depressed. It is to be noted that as soon as sequence switch 200 leaves position 1%. relay 201 is maintained energized over a circuit. extending through the lower contacts of sequence switch spring 202, the left hand armature and back contact of relay 208. the upper right-hand. and lower left hand contacts of sequence switch spring to ground. The test terminals associated with district switch circuits, whose controlling sequence switches are in any other position than position 2, are characterized by the absence of ground. Theretore CGSb relay 208 does not become energized until the cord tinder test brush 210 engages test terminal 211, whereupon a circuit is completed from grounded battery, winding of relay 20S, upper contact of sequence switch spring 212, test brush 210, test terminal 211, conductor 213, upper contacts of sequence switch spring 115, outer right-hand armature and back contact of relay 106, lower contacts of sequence switch spring 111 to ground. lay 208 is energized and at its left-hand armature opens the circuit of relay 201. Relay 201 remains energized for an instant longer due to a locking circuit extending from inner right-hand armature and trout contact. commutator 214;, commutator brush to ground. W'he-n, an instant later, comma-- tator brush 215 engages an insulating seg ment of commutator 214, at which time the cord finder brush set will be correctly centered on the selected terminal set, relay 201 is deenergized and opens at its outer righthand armature the driving circuit of magnet 207, which deenergizes and allows the cord finder to come to rest. The deenerg'ization of relay 201 completes a circuit from grounded battery, power magnet of sequence switch 200, lower left-hand contact of sequence switch spring 200. outer right-hand armature and back contact ot relay 201 to ground. for moving this sequence switch out of position 2 and into position 3.

The operation of the sender selector shown at the right of Fig. 2 is simultaneous with the operation ot the cord finder. It will be recalled that rel y 20% was energized upon the initial energization of relay 201 to cause the advance of sequence switch 200 into position 2. When sequence switch 200 leaves position 1%, the energizing circuit o't relay 204 is interrupted at the. right-hand contact of sequence switch spring 205. but if at this time the first sender is busy. which will be indicated by the fact that its control-- ling sequence switch 300 is in some position other than 1, a locking" circuit is completed through th left-hand winding of relay "204., left-hand armature and front contact. of relay 20d, left-hand contacts of sequence switch spring 216. sender selector brush. 217, which is engaging testterminal 218 ot the set of terminals associated with the first sender, conductor 219, right-hand winding of relay 301,, upper left-hand and lower right-hand contacts of sequence switch spring 302 to ground. ll it-h sequence switch 200 in position 2-, a circuit is completed from grounded battery, winding of "up-drive magnet 220 of the sender selector, contacts of sequence switch spring 221, inner right-hand ture and trout. contact of relay 204 to ground. :t 220 is energized in this circuit and causes the sender selector brush shaft. to he moved upward in search of an idle sender. is soon as test brush 217 enl a test terminal 219- on which there is no ground potential, the locking; circuit of relay 30% is broken, Relay 201i.- is maintained energ d a moment longer, however, due to the e:\ stence ot a circuit extending from grounded battery, right-hand winding ot relay 20 t, lower left-hand and upper ri ht-ha d contacts o't sequence switch 2212, conducting segment or" commuilttt)? 323, commutator brush to ground. ll hen, a moment later, brush 224- engages an insulating segment of commutator 223, at which time the sender selector brush set will be accurately centered on the terminal set of an idle sender, the circuit through the right-hand winding of relay 20 is' broken and this relay deenergizes, causing in turn the deenergiaaticn ot up drive magnet 220, thus bringing the sender selector to rest. It is to be obserred that it the sender selector is the first to conuplete its operation the sequence switch 200 will remain in posi tion 2 until the cord finder has completed ts operation. whereupon it will he moved into position 3. The deenergization of relay QO-Lt then completes a circuit from grounded liattery, power magnet of sequence switch 900, lower right-hand contact of sequence switch spring 200, inner right-hand armature and back contact; of relay 20st to ground, for i'novino this sequence switch out of po sition 3 and into position l.

li the cord tinder is the first to complete its operation. the sequence switch 200 will be advanced out of position 2 and into position 3 as previously described. In position the operation of the sender selector will continue as above described, since thecir on its therein traced in each case function to the same purpose whether the sequence switch is in position 2 or position 3 as may be readily ascertained by inspection of the drawing. I i

soon as the sender circuit shown in Figs. 3, t and has heen seized and the sequence switch 200 has reached position 4, a circuit is completed from grounded battery. lefthand winding ot relay 301. (Fig. 3), upper right-hand and lower left-hand contacts of sequence switch spring 303. conductor 30 1, terminal 225. brush right-hand contacts of sequence switch spring 227, to ground. Relay 301 is energized in this circuit and locks up through its left-hand armature and front contact to conductor 219 which is grounded by way of the upper left-hand and lower right-hand contacts of sequence switch spring 216. Ground potential is also supplied to test terminal 918 to render this sender non-selectable to other limiting sender selectors. Relay 301 upon energization also completes a circuit fromgrounded battery, power magnet of sequence switch 300, lower left-hand contact of sequence switch spring 305, left-hand armature and front contact of relay 301 to ground for moving this sequence switch out of position 1 and into position 6.

lVith sequence switch 200 in position at and sequence switch 100 in position 2, a circuit .is completed from grounded battery, right-hand winding of relay 20 1, left-hand contacts of sequence switch spring 222, inner right-hand armature and front contact of relay 228, which was energized when test relay 208 operated incident to the finding of the desired cord, cord finder brush 229, terminal 230, conductor 231, lower contact of sequence switch spring 116 to ground. Relay 204. is energized in this circuit and completes a circuit from grounded battery, power magnet of sequence switch 200, upper right-hand contact of sequence switch spring 206, inner righthand armature and front contact of relay 204, to ground for moving this sequence switch out of position 1 and into position 5.

As soon as sequence switch 200 reaches position 5, a circuit is completed from grounded battery, power magnet of sequence switch 100, conductor 117, lower contacts of sequence switch spring 118, conductors 119 and 120, terminal 232, brush 233, outer left-hand armature and front contact of relay 228, upper contact of sequence switch spring 234, to ground, for moving sequence switch 100 out of position 2 and into position 3.

As soon as sequence switch 100 leaves position 2, the energizing circuit of relay 20 1 is broken and this relay deenergizes and completes a circuit from grounded battery, power magnet of sequence switch 200, lower right-hand contact of sequence switch spring 206, inner right-hand armature and back contact of relay 204 to ground for moving this sequence switch out of position and into position 6.

As soon as sequence switch 100 reaches position 3, a circuit is completed from grounded battery, left-hand winding of relay 106, lower right-hand contact of sequence switch spring 121, conductor 122, lower contact of sequence switch spring 123, to ground. Relay 106 is energized and completes a circuit from grounded battery, power magnet of sequence switch 100, conductor 117 left-hand contacts of sequence switch spring 124, inner right-hand armature and front contact of relay 106, upper contacts of sequence switch spring 109 to ground for moving this sequence switch out oi position 3 and into position 5. As soon as sequence switch 100 leaves position 3 the energizing circuit of relay 106 is broken and this relay deenergizes. The district sequence switch remains in position 5 until the fundamental circuit for controlling the selective operation of the switch is completed.

The operation of setting up the wanted number on the various registers will now be described. As previously mentioned, the operator is provided with a set of keys to control office selection comprising a row of horizontal keys indicated generally at H in Fig. 6 and numbered from 1 to 10 and a row of twenty vertical keys shown generally at V, Fig. 6, and numbered from 1 to 20. She is also provided with a keyset provided with ten keys for each digit in the wanted number, these ten keys representing respectively the ordinals from 0 to 9. The numerical keys and the method in which they function to control registers has not been described.

The incoming call is to be diverted to the attention of an operator at a local desk. Assuming that the office code corresponding to a call which is to be routed to a local desk is AX, the cordless operator will im mediately after depressing assignment key 112, as previously described, depress key No. 7 in the H row and key No. 15 in the V row.

As soon as key A is depressed, a circuit quence switch spring 702, conductors 703 and 7 04, right-hand contacts of key A, conductor 600 to ground. Relay 701 is energized in this circuit and completes a circuit from grounded battery, power magnet of sequence switch 700, conductors 705 and 706, upper right-hand contact of sequence switch spring 707, right-hand armature and front contact of relay 701 toground for moving this sequence switch out of position 1 and into position 2. As soon as sequence switch 700 reaches posit-ion 1%, relay 701 completes a locking circuit for itself through its righthand armature and front contact and the left-hand armature and back contact of relay 708 to ground by way of the upper lefthand contact of sequence switch spring709.

In position 2 of sequence switch 7 00,brush selection is accomplished by the translator switch shown in Fig. 6. The circuit of updrive magnet 601 extends from grounded battery, winding of magnet 601, conductor 602, upper left-hand and lower right-hand contacts of sequence switch spring 710, lefthand armature and front contact of relay 701 to ground. It is to be observed that with sequence switch 700 in position 2, relay 603, Fig. 6, is energized over a circuit extending from grounded battery, winding of relay 603, conductor 604, right-hand contact of sequence switch spring 711 to ground.

During the upward movement of the translator brush shaft, commutator test brush. 605 successively engages the commutator segments in the right-hand group of the main commutator plate 606. The first five contacts to be engaged by brush 605 are utilized to determine wl ici set of brushes shall be selected. Each brush set serves a group of forty terminal sets. These forty terminal sets are arranged in a continuous group. A novel controlling circuit has been introduced, the operation of which will be subsequently described, so that in case the desired tern'iinal set is in the lower twenty, the selected brush set will begin hunting starting from the lowermost terminal in the lower twenty. In case, however, the desired terminal set is in the upper twenty, the selected brush set will be moved over the contacts of the lower twenty without hunting in such group and will come to rest with its brushes in engagement with the lowermost terminal set in the upper twenty. Thereafter it will be caused to hunt for the proper terminal set. From this it is obvious that the selection of the desired one of two hundred terminal sets is accomplished, first, by selecting one of five brushes to select a group of forty terminals. Selection is then made to select an upper or lower group of twenty terminals, after which the desired terminal is selected. The selection of a brush set and the selection of a twenty group is made under thecontrol of a key in the horizontal column. The selection of the particular contact in the twenty group is always under the control of a key in the vertical column.

The translator brush shaft is moved upwardly as described until commutator brush 605 engages commutator segment 607, at which time a circuit is completed from grounded battery, winding of relay 708, right'hand contact of sequence switch spring 712, conductor 713, brush 605, segment 607, armature 608 and its front contact, conduc-- tors 609 and 610, closed lefthand contacts of key A, conductor 611, lower right-hand contact of sequence switch spring 709 to ground. Relay 708 is energized in this circuit and locks up to ground through its right-hand armature and the upper righthand contact of sequence switch spring 709. Relay 708 at its left-hand armature opens the locking circuit of relay 7 01. Relay 701 is maintained energized a moment longer, however, dire to the existence of a circuit extending by way of conductor 714;, a conducting segment of commutator 612. commutator brush 613 to ground. When, a moment later, commutator brush 613 engages an insulating segment of commutator 612, at which time the selected brush set will be accurately positioned for brush tripping, relay 701 is deenergizecl and at its left-hand armature opens the circuit of updrive magnet 601, causing the translator brush shaft to be brought to rest. The deenergization of relay 701 also completes a, circuit from grounded battery, power magnet of sequence switch 700, conductors 705 and 706, lower right-hand contact 707 and back contact of relay 701 to ground, for moving this sequence switch out of position 2 and into position 3.

In position 3 of sequence switch 700, a circuit is completed from grounded battery, winding of trip magnet 61t, conductor 615, lefthand contact of sequence switch 711 to ground. Trip magnet 614: is energized and operates the trip rod controlled by it so that upon the subsequent upward movement of the translator switch the second set of brushes will be released into operative relation with the group of terminals served by it.

The keys numbered from 1-5 inclusive in the horizontal row are arranged to cause a selected brush set to hunt for a particular one of twenty terminals in the lower twenty of a selected group of forty terminals. This is a accomplished due to the fact that ground is supplied to conductor 720 by way of the right-hand contacts of such keys when actuated. Any one of keys 6 to 10 in the hori zontal row when actuated determine that hunting for the desired terminal set shall take place after the lower twenty group has been traversed. This is accomplished by supplying ground to conductor 701 by way of the right-hand contacts of such keys. The manner in which the discrimination between twenty groups is accomplished will now be described.

Since key A has been depressed, which is one of the keys numbered 6 to 10 in'the horizontal group, the desired terminal set is located in the upper twenty. Therefore, with sequence switch 700 in position 3, a circuit is completed from grounded battery, winding of relay 701, upper right-hand con tact of sequence switch spring 702, conductors 703 and 7 0%, closed right-hand contact of key A, conductor 600 to ground. Relay 701 is energized in this circuit and locks up through its right-hand armature and front contact and the left-hand armature and back contact of relay 708, which was deenergized when sequence switch 7 00 left position 2, to ground by way of sequence switch spring 709. Relay 701 at its left-hand armature completes a circuit from grounded battery, power magnet of sequence switch 7 00, upper righthand contact of sequence switch spring 707, left-hand armature and front contact of relay 701 to ground for moving this sequence switch out of position 3 and into position 4.

In position. iof sequence switch 700, a circuit is completed from grounded battery, winding of up-drive magnet 601, conductor 602, upper left-hand and lower right-hand contacts of sequence switch spring 710, lefthand armature and front contact of relay 7 01 to ground. No test of the terminals in the lower twenty made as ceinn'iutator brush 605 passes over the commutator segments corresponding to such terminal sets. However, as soon as test brush 605 engages the comn'iutator segment corresponding to the lowermost terminal set in the upper group of twenty, which is segment (318, a circuit is completed from grounded battery, winding of relay S, right-hand contacts of sequence switch spring 712, conductor 713, brush 605,

terminal 618, conductor 619, lower left-hand contact oi sequence switch spring 715, eonductor 701 closed right-hand contacts of the A key, conductor (500 to ground. Belay 708 is energized in this circuit and at its lefthand armature opens the locking circuit of relay 701. Relay 701 remains energized as previously described until the brush set is accurately centered, whereupon it deenergizes and completes a circuit from grounded battery, power magnet of sequence switch 700, conductors 7 05 and 706, lower righthand contact of sequence switch spring 707, left hand armature and back contact of relay 701, to ground, for moving this sequei'ice switch out of position -i and into position Relay 708 is deenergized as soon as sequence switch 700 leaves position 4.

As soon as sequence switch 700 reaches position 5, a circuit is completed from grounded battery, winding o't relay 701, conductor 716, contacts of sequence switch spring 717, conductor 718, closed right-hand contact of key X, conductor 619 to ground. Relay 701 is energized and completes a circuit for moving sequence switch 700 out of position 5 and into position 6, identical with the circuit traced for moving it from position 3 to position Relay 701 upon energization locks up through the left-hand armature and back contact of relay 708 as previously described.

In position 6 0t sequence switch 700, the translator switch is moved upwardly in its final hunting movement, the circuit of updrive magnetGOl extending to ground at the left-hand armatruie and front contact of relay 7 1 over a path previously described.

lVhen test brush 005 engages commutator segment (520, which is the segment in the upper twenty. associated with ltey X, a cir cuit is completed from grounded battery, winding or" relay 708, contacts of sequence switch spring 712, conductor 713, brush 605, segment (3'20. conductor 621, closed lett-hand contact ot key X, conductor 622. upper right-hand contact oi sequence switch spring 719 to ground. Relay 708 is energized in this c 'cuit and opens at its left-hand armature the locking circuit of relay 701. When, a moment later. commutator brush 01? en an insulating segment of commutator 612 relay 701 deenergizes and opens the circuit of tip-drive magnet ($01, allowing the translator brush shaft to come to rest with the second set of brushes in engagement with the thirty-fifth terminal set in the group served by it. Relay 701, upon deenergization, also completes a circuit from grounded battery, power magnet of sequence switch 700, conductors 705 and 706, lower righthand contact of sequence switch spring 707, left-hand armature and back contact of relay 701 to ground for moving this sequence switch out of position 6 and into position 7.

In order that the setting operation of the translator switch may be more fully undertood, its operation when a terminal set in the lower twenty is to be selected will be briefly described. It will be assumed that lrey E in the horizontal row has been depressed and that ltey X in the vertical row has been depressed. In this case, when sequence switch 7 00 reaches position 2, the translator switch is moved into position to select the second set of brushes in a manner identical with that previously described, and sequence switch 700 is then moved into position 3. 7 01 in position 3 of sequence switch 700 under the assumptions that have now been made. Sequence switch 7 00 is, however, immediately moved out of position 3 by means of a circuit extending from grounded battery, power magnet of sequence switch 700, conductors 705 and 706. upper left-hand contact oi sequence switch spring 707, conductor 720, closed right-hand contacts of key E to ground. As soon as sequence switch 700 reaches position a, it is immediately moved out of position a and into position 5 by means or a circuit extending from ground battery, power magnet otsequence switch 700, conductors 705 and 706. lower righthand contact of sequence switch spring 707, left-hand armature and back contact of relay 701 to ground. Sequence switch 700 is then moved out of position 5 and into position 6 by means of circuits previously described. ln position 6, up-drive magnet 601 is again energized and the translator brush shaft, is moved upwardly. When commutator brush 605 engages commutator segment 623, a circuit is completed from grounded battery, winding of relay 708, contacts of sequence swtch spring 712, conductor 713, brush 605. terminal 623, conductors 62 i and (321, closed left-hand contacts of key X and thence to ground as previously described. In this case the translator brush is brought to rest with its selected brush set in engagement with the fifteenth contact set in the group of terminals served by .it.

As soon as the translator switch is positioned the first transfer of the ofiice registration has been accomplished since the position assumed by such translator switch determines what district and oliice selections are to be made. The method of transferring No circuit is found for relay this registration from the translator switch to the register relays shown in F 7 by means of the impulse sending device indicated generally at will now be described.

The imnulser as shown in Fig. 6 is pro-- vided with eleven sending drums and 'ociated brushes and with four receiving drums and associateiil brushes. The sending drum brushes have been numbered from 626 to 636 inclusive while the receiving drum brushes have been numbered from 637 to 640 inclusive. It is obvious that the terminals in the translator switch bank may be variably wired to the sending brushes in any desired combination to control the reg istration of the various designations necessary to control. otlice selection. The distributing frame whereby such variable wiring mayreadily be accomplished is indicated generally at 690 in the drawing.

Referring now to Fig. 7, it is to be. noted that with sequence switch 700 in position 7, a circuit is completed from grounded battery, winding of relay 721, upper left-hand contact of sequence switch spring to ground. Relay 721 is energized in this circuit.

Assuming that the position of the. brushes with respect to the conducting segments on the impulser 625 at the instant Sfiqllllt'e switch 700 reaches position 7 is that shown in Fig. 6, the operation of the register relays of Fig. 7 is as follows. it bein remembered that the segments included within the rectangle at 625 are connected to grounded battery. The impulser will rotate. until brushes 627, 631 and 632 make contact with segments 641, 642, 643 and 644 respectively. As a result of these contacts, the following circuits are completed: grounded battery, segment 643, brush 631, terminal 645, brush 646, conductor 647, armature 723, winding of relay 724 to ground: grounded battery, segment 642, brush 627, terminal 648, brush 649, conductor 650, armature 725, winding of relay 726 to grouiul: grounded battery, segment 644, brush 632. terminal 651, brush conductor 654, armature 727 winding of relay 728 to ground. Relays 724, 726 and 728 are energized as a result of the completion of these circuits and complete obviously traced energizing cir- .cuits for relays 729, 730 and 731.

hen brush 633 engages segment 655, circuits are completed for relays 732, and 734 respectively. The circuit of relay 732 extends from ground, left-hand winding of relay 732, arn'iature 735 of relay 731, conductor 736, brush 638, segment to ground ed battery. The circuit of relay 733 extends from ground, left-hand winding of relay 733, armature 737 of relay 730, conductor 736 and thence to grounded battery as described. The circuit of relay 734 extends from ground, left-hand winding of relay 734, armature 738 of relay 729 and thence to grounded batter Relay upon energization locks up through its right-hand winding and righthand armature and front contact to conductor 739 which is grounded at the lower right-hand contact of sequence switch spring 715/. Relay 733 completes a similar locking circuit to grounded conductor 740 and relay 734 completes a locking circuit to grounded conductor 739. As soon as the sending brushes 626, etc. leave their associated segments, relays 726, 728 and 724 deenergize causing in turn the deenergization of relays 729, 730 and 731.

The impulser continues to rotateand when the second vertical row of segments comes into engagement with the brushes served by them, another set of circuits is completed. These circuits are as follows: grounded battery, segment 656, brush 627, terminal 648,

brush 64.9, conductor 650, armature 725, winding of relay 726 to ground; grounded battery, segment 658, brush 632, terminal 651, brush 653, conductor 654, armature 727, winding of relay 728 to ground: grounded battery, segment 659, brush 634, terminal 660, brush 661, conductor 662, armature 741, winding of relay 742 to ground. Relays 726, 728 and 742 are energized and complete energizing circuits for relays 729, 730 and 749- respectively. As soon as brush 639 engages conducting segment 663, which is the next receiving drum segment, circuits are completed for relays 743, 744 and 745. The circuit of relay 743 extends from ground, lefthand winding of relay 743, armature 7 460i relay 729, conductor 747, brush 639, segment 663 to grounded battery. The circuit ofrelay 744 extends from ground, left-hand winding of relay 744, armature 748 of relay 749, which was energized when relay 742 was energized, conductor 747 to grounded battery. The circuit of relay 745 extends from ground, left-hand winding of relay 7 45, armature 7 50 of relay 730, conductor 747 to grounded battery. As soon as brush 639 leaves segment 663 the energizing circuits of relays 743, 744 and 745 are broken but these relays are maintained. energized due to the completion of locking circuits through their right-hand windings. As soon as the com niutator brushes leave the second vertical. row of segments, relays 726, 742 and 728 are deenergized causing in turn the deene-rgization of relays 729, 749 and 730.

As soon as the third vertical row of seg ments of the impulser come into contact with the impulser brushes the following circuits are completed: grounded battery, segment 664, brush 631, terminal 645, brush 646, conductor 647, armature 723, winding of relay 724 to ground: grounded battery, segment 665, brush 632, terminal 651, brush 653, conductor 654., armature 727, winding of relay 728 to ground: grounded battery, segment 666, brush 634, terminal 660, brush 661, conductor 662, armature 741, winding of relay 742 to ground: grounded battery, segment 667, brush 635, terminal 672, brush 673, conductor 674, armature 751, Winding of relay 752 to ground: in parallel with the last circuit, from grounded battery, segment 667, brush 635, terminal 669, brush 670, conductor 671, armature 754, relay 755 to ground. Relays 752, 742, 728, 724 and 7 are energized as a result of the completion of these circuits, causing in turn the energization of relays 753, 749, 730, 731 and 756. When receiving brush 640 engages segment 668, circuits are completed for energizing relays 757, 758, 759, 760 and 761. The circuit of relay 7 57 extends from ground, left-hand winding of relay 757, armature 762 of relay 753, conductor 763, brush 640, segment 668 t grounded battery. The circuit of relay 7 58 extends from ground, left-hand winding of relay 758, armature 764, conductor 763 to grounded battery. The circuits of relays 759, 766 and 761 are obviously traceable in View of the previous description. vVhen segment 668 leaves brush 640, the energizing circuits over the lefthand windings of relays 757 to 761 inclusive are broken, but these relays remain locked up through their right-hand windings. As soon as the third vertical row of segments passes from engagement with their associated brushes, relays 752, 7 42, 728, 724 and 7 55 are deenergized causing in turn the deenergization of relays 753, 729, 749, 730, 731 and 756. f r

T ien the fourth vertical row of segments engages the associated brushes, the following circuits are completed: from grounded battery. segment 674. brush 634, terminal 660, brush 661, conductor 662, armature 7'41, winding of relay 742toground: from grounded battery, segment 675, brush 635, terminal 672- brush 673, conductor 674, armature '7 winding of l relay 752 to ground: in parallel with the last traced circuit, from grounded battery, segment 675. brush 635, terminal 669, brush 670, conductor 671, armature 754, winding of relay 755 to ground. Relays 752, 742 and 755 are energized as a result of the completion of these circuits causing in turn the energization of relays 753, 749 and 756.

\Vhen segment 676 engages brush 637, energizing circuits are completed for relays 765:. 765 and 766. The circuit of relay 764 extends from ground. lefthand winding of relay 7 64. innermost. armature of relay 7 53. conductor767. brush 637, segment 676 to rounded battery. The circuits of relays 765 and 766 are readily traced in View of the previous description. When segment 676 passes from engagement with its assoa. ted brush 637, the energizing circuits of relays 765 and 766 are brolren, but theie rel:

remain energized due to the closure of locking circuits through theirright iand windings and right-hand armatures and front contacts. When segments 674 and 675 pass out from under their associated brushes, relays "752, 742 and 755 are deenergized causing in turn the deenerization of relays 753, 749 and 756. All of the register relays of Fig. 7 which must be actuated to receive the full registration have now been energized. It is therefore obvious that a single revolution of the impulser 625 serves to control the complete registration.

It is to be observed that only one impulser is needed to serve the entire' exchange. The brushes of the impulser may be wired to the contacts in the terminal bank as required and may be multiplied whenexer necessary without danger of interference between the various translator switches, since the relays of the register set 7 shown in Fig. 7 are affected only by the position of the particulartranslator switch associated with them.

' Consideration of the register relays of Fig. 7 will show that they are twenty-four in number, divided into six lateral rows of four relays each. The first lateral row of relays is used to control peg count, the second row controls class registration, the third row controls district brush registration, the fourth row controls district group registration, the fifth row controls office brush registration and the sixth row controls ofiice group registration. There is a corresponding brush on the translator for each row of relays, or each separate regis ter as they may be considered to be.

There are as many impulse receiving as there are relays in each register, that is, since there are four relays in each register, it follows that there are four impulse receiving stages. During the first impulse receiving stage (which was described last in the description just given in View of the position in which the impulser was assumed to be at the start of operations) the No. i relays vin each register are actuated provided that the brushes corresponding to such registers are connected to brushes which at that instant are making contact to grounded battery through the impulse machine. Similarly during the second receiv "ing stage,*which occurs when segment 655 engages brush 638, all the No. 2 relays in the various registers which are ultimately to be operated will be operated and so on.

:rfter the register relays shown in Fig. 7 have been actuated, it is essential that the controlling sequence switch 700 be advanced and the translator switch be restored since it performs no further function, its registration having been transferred to the relays ofv Fig. 7.

In order to insure that a com-' plete revolution of'th impulser may take place before the advance of sequence switch 7.00, Counting relays 768 to 770 are provided. Referring now to Fig. 6, when segment 657 engages brush 629 a circuit is completed from grounded battery, segment 657, brush 62 9, conductor 677, inner righthand armature and front contact of relay 721, winding of relay 771 to ground. Relay 771 is energized and completes a circuit from grounded battery, winding of relay 7 6S, armature and back contact of relay 769, armature and front contact of relay 771 to ground. Relay 768 is energized and completes a locking circuit for itself including the winding of relay 769. The relay 769 is not energized at this time, however, since it is shunted by the presence of direct ground at the armature and contact of relay 771. As soon as segment 657 passes from engagement with brush 62 9, relay 771 deenergizes and allows counting relay 769 to be energized. \Vhen segment 67.8 engages brush 629, relay 771. is again energized and allows the lower counting relay of the second pair to become energized and prepare a circuit for the upper counting relay of such second pair. As soon as segment 678 passes from engagement wit-h brush 629, relay 771 is deenergized and allows the upper counting relay of the second pair to be energized and prepare a circuit for the lower counting relay of the third and last pair. After the impulser has completed a complete revolution, and again causes segment 657 to engage brush 629, the lower counting relay of the last pair is energized and when segment 657 breaks engagement with brush 629, relay 770 is energized. It is obvious that, regardless of the position of the iinpulser at the time of the start of the register setting operation, three makes and three breaks of contact at brush 629 must be made before the sequence switch 700 can be advanced out of position 7. It .is also apparent that the setting of the relays which constitutes the various registers will take placein proper order and without possibility of wrong settings regardless of the position of the impulse switch at the time that the setting operation is begun.

lVhen relay 770 is energized, a circuit is completed from grounded battery, power magnet of secpiencc switch 700 lower let hand contact of sequence switch spring 772, right-hand armature and front contact of relay 770 to ground. for moving this queuce switch out of position 7 and into position 8.

As soon as sequence switch 700 leaves position 7. relay 721 is deenergized and coinpletes a circuit from grounded battery, winding of down-drive magnet 6'79, con .ductor 6S0, outer light-hand armature and back contact of relay 721, lower contact of sequence switch spring- 722 to ground. The translator switch is returned to its normal position under the control. of magnet 6'79 and when the translator brush shaft reaches its normal position, as evidenced by the engagement of commutator brush 13 with normal commutator segment 681, a circuit is completed from grounded battery, winding of relay 721, lower left-hand and upper right-hand contacts of sequence switch spring 710, conductor 773, commutator seg ment 681, brush 613 to ground. Relay 721 is energized and opens the circuit of downdrive magnet 679.

The operation of transferring the registration from the relays of Fig. 7 to the relays of Fig. will now be described.

When sequence switch 700 reaches position a circuit is completed from grounded battery, right-hand winding of relay 502 (Fig. 5), conductor 503, lower contacts of sequence switch spring 308, closed due to the fact that sequence switch 300 is in position 6, conductors 309, 310 and 311, terminal 240, brush 24, conductors 2&2 and 243, upper left-hand and lower right-hand contacts of sequence switch spring 2&4, conductor 245, upper right-hand contact of sequence switch spring 774;, left-hand armature and front contact of relay 734 to ground. Relay 502 is a marginal relay but due to the fact that direct ground is supplied to its right-hand winding it becomes energized and locks up tl'irough its lef hand. armature to conductor 50% which is grounded at the upperrighthand contact of sequence switch spring 312.

hen sequence switch 700 reaches position 8, a circuit is completed from grounded battery, right-hand winding of relay 500 (Fig. conductor 501, upper contacts of sequence switch spring 306, which are closed due to the fact that sequence switch 300 is in position 6, conductor 307. terminal brush 236, conductor 237, lower contact of sequence switch spring 238, conductor 239, upper right-hand contact of sequence switch. spring 775, through the right-hand armatures and front contacts of relays 7 43 and 734 in parallel, conductor 776, rigl'it-hand and lefthand windings of relay 777 in series, upper arniature and back contact of relay 778 to ground. Relay 777 is energized in this circuit but marginal relay 500 is not energized, due to the fact that the high resistance winding of relay 777 was included in this circuit. Relay 777 upon energization locks up through its inner left-hand armature and front contact and in so doing removes the shunt from about the winding of relay 778. allowing this relay to be energized due to the completion of a circuit extending from grounded battery, resistance 779, upper lefthand contact of sequence switch spring 780. winding of relay 778 to ground. This last mentioned circuit was previouslv in existence, but relay 778 was shunted by the presence of ground supplied by way of the lower armature and back contact of relay 778 and the inner left-hand armature and back contact of relay 777.

With sequence switch 700 in position 8, a circuit is also completed from ground, righthand winding of relay 505, conductor 506, upper contacts of sequence switch spring 313, conductor 314, terminal 246, brush 247, lower contact of sequence switch spring 248, conductor 249, lower contact of sequence switch spring 781, left-hand armature and front contact of relay 743, low resistance 782 to grounded battery. Relay 505 is energized in this circuit and locks up through its lefthand winding and left-hand armature and front contact to grounded conductor 504.

As soon as relay 777 is energized, a circuit is completed from ground, winding of relay 315 (Fig. 3), upper contact of sequence switch spring 316, conductor 321, right-hand winding of marginal relay 507, conductors 508 and 322, terminal 250, brush 251, conductor 252, upper right-hand contact of sequence switch spring 783, conductor 784, high resistance 785, conductor 786, outer left-hand armature and front contact of relay 7 77, low resistance 787 to grounded battery. Relay 315 is energized in this circuit but relay 507, being marginal, does not become energized due to the inclusion in its circuit of high resistance 785. The energization of relay 315 completes a circuit from grounded battery, power magnet of sequence switch 300, armature and front contact of relay 315, lower left-hand and upper righthand contacts of sequence switch spring 317, armature and back contact of relay 318 to ground for moving this sequence switch out of position 6 and into position 7.

As soon as sequence switch 300 leaves position 6, the energizing circuit for relay 777 is opened and this relay deenergizes, completing a circuit from grounded battery, power magnet of sequence switch 700, lower contact of sequence switch spring 788, lefthand armature and back contact of relay 789, lower armature and front contact of relay 778, inner left-hand armature and back contact of relay 777, to ground for moving this sequence switch out of position 8 and into position 9. As soon as sequence switch 700 leaves position 8, the circuit of relay 778 is broken at sequence switch spring 780 and this relay deenergizes.

In position 9 and 7 of sequence switches 700 and 300 respectively, the setting of the registers in Fig. 5 is continued. This operation is as follows.

hen sequence switch 700 reaches position 8% a circuit is completed from ground, right-hand winding of relay 509, right-hand windingof marginal relay 510, conductor 511, contacts of sequence switch spring 323, conductor 307, terminal 235, brush 236, conductor 237, lower contact of sequence switch spring 238, conductor 239, upper left-hand contact of sequence switch spring 775, lefthand armature and front contact of relay 765, low resistance 7 82, to grounded battery.

Since only a low resistance is included in this circuit, both relays 509 and 510 are energized in spite of the fact that relay 510 is marginal. These relays upon energization lock up to grounded conductor 504. At the same time a circuit is completed from H ground, right-hand winding of relay 512, right-hand winding of marginal relay 513, conductor 514, lower contacts of sequence switch spring 325, conductor 322, terminal 250,.brush 251, conductor 252, lower lefthand contact of sequence switch spring 790, left-hand armature and front contact of relay 732, high resistance 791, low resistance 792 to ground. Due to the presence of the high resistance 791 in this circuit, relay 513, which is marginal, does not become energized. Relay 512 does, however, become energized and locks up through its left-hand winding.

hen sequence switch reaches position 9, a circuit is completed from grounded battery, left-hand winding of marginal. relay 515, conductor 516, lower contacts of sequence svitch spring 324, conductor 314, terminal 246, brush 247 contact of sequence. switch spring 248, conductor 249, upper right-hand contact of sequence switch spring 781, outer righthand armature and front contact of relay 7 32, outer right-hand armature and front contact of relay 765, conductor 793, high and low resistance windings of relay 789 in series to ground through the upper armature and back contact of relay 794. At the same time a parallel path is closed extending through the left-hand armature and front contact of relay 744, upper contact of sequence switch spring 795, conductor 796, low resistance right-hand winding of relay 7 89 and thence to ground. Relay 789 is energized in this circuit and due to the fact that the last traced parallel path short-cir cuits the high resistance of the left-hand winding of relay 789, marginal relay 515 (Fig. 5) is allowed to energize. Relay 515 upon ener gization locks up to grounded conductor 504. Relay 789, upon energize.- tion locks up through its inner right-hand armature and front contact and at the same time removes the shunting ground which has been preventing the energization of relay 794. Relay 794 is now energized due to the completion of a circuit from ground.- ed battery, resistance 779, right-hand contact of sequence switch spring 780 and the winding of relay 794 to ground. 1

The energization of relay 789 completes a circuit from ground, winding of relay 318 (Fig. 3) upper contact of sequence switch spring 320, conductor 326, left-hand windof marginal relay 517, conductors 518, 310 and. 311, terminal 240, brush 241, conductors 242 and 2413, upper left-hand and lower right-hand contacts of sequence switch spring 244, conductor 2&5, upper let'tmud contact of sequence switch spring 77%, through the high resistance 785, c onluctor 783, outer right-hand armature and front contact of relay 789, low resistance 7 87 to grounded battery. Due to the presence of the high resistance 785, relay 517 cannot become energized. Relay 318 does, however, become energized and completes a circuit from grounded battery, power magnet oi sequence switch 300, armature d bacl: contact of relay 315, upper leftnd and lower right-hand contacts of sequence switch spring 317, armature and front contact of relay 318, to ground for moving this sequence switch out of position 7 and into position 8.

As soon as sequence switch 300 leaves po* sition 7, relays 318 and 789 are deenergized. The deenergization of relay 789 completes a circuit from grounded battery, power magnet of sequence switch 700, upper contact of sequence switch spring 788, right-hand arn'iature and back contact of relay 777, lower armature and front contact of relay 79%. inner right-hand armature and back contact of relay 789 to ground for moving this sequence switch out of position 9 and into position 10. As soon as sequence switch 700 leaves position 9, the holding circuit of relay 794 is broken and this relay deenergizes.

When sequence switch 700 reaches position a circuit is completed from ground, right-hand winding of relay 519, right-hand winding of marginal relay 520, conductor 521, right-hand contact of sequence switch spring 327, left-hand contact of sequence switch spring 313, conductor 314, terminal brush 247, contact of sequence switch spring 248, conductor 249, upper left-hand contact of sequence switch spring 781, lefthand armature and front contact of relay 733, high resistance 797, low resistance 782 to grounded battery. Due to the presence of high resistance 797 in this circuit, relay 520 does not become energized. Relay 519 does, however, become energized and loclcs up to grounded conductor 504.

hen sequence switch 700 reaches position 10, a circuit is completed from grounded battery, left-hand winding of marginal relay 522, conductor 523, upper contact of sequence switch spring 328, left-hand contact of sequence switch spring 306, conductor 307, terminal brush 236, conductor 237, contact of sequence switch spring 238, conductor 239, lower-left-hand contact of sequence switch spring 775, outer right-hand armature and front contact of relay 733, conductors 798 and 776, high and low resistance windings of relay 777, outer armature and back contact of relay 778 to g, cund. Due to the fact that the high resistance right-hand winding otrelay 777 has been included in this circuit, marginal relay does not becon'ie energized. Relay 777 does, however, become energized and locks up through its inner left-hand armature and front contact and allows relay 778 to operate in the manner previously de scribed. The one pletes a circuit from grouiid, winding of relay 315 (Fig. lower contacts of sequence switch spring 319. conductor 329, right-hand winding of marginal relay conductors 508 and terminal 250, brush 251, conductor 252, upper right-hand contact of sequence switch 783, conductor 784, high resistance 785, conductor 786, outer left-hand armature and front contact of relay 777, low resistance 787 to grounded battery. lay 315 is energized in this circuit, but relay 52-1 cannot become energized due to the presence of high resistance 785'. There is in addition, however, a circuit extending from conductor 252 by way of the upper left-hand contact of sequence switch spring 790, lefthand armature and front contact of relay 759 and thence by way of conductor 799 to conductor 786 and to grounded battery as previously described. It is to be observed that this last traced circuit short circuits the high resistance 785 and renders it inetlecti-ve. Therefore, relay is energized and locks up through its left-hand armature. The energization of relay 315 completes a circuit from grounded battery, power magnet of sequence switch 300, armature and front contact of relay 315, lower left-hand and upper right-hand contacts of sequence switch spring 317, armature and back contact of relay 318 to ground for moving this sequence switch out of position 8 and into position 9. As soon as sequence switch 300 leaves position 8, relays 315 and 777 are deenergized. Relay 777 upon deenergizzu from. grounded battion completes a circuit tery, power magnet of sequence switch 7 00, lower right-hand contact of sequence'switch spring 788, left-hand armature and back contact of relay 789, lower armature and front contact-of relay 778, inner left-hand armature and back contact of relay. 777 to ground, for moving this sequence switch out of position 10 and into position 11. As soon as sequence switch 700 leaves position 10, relay 778 is deenergized.

lVhen sequence switch 7 00 reaches position 105}, a circuit is completed from ground, right-hand winding of relay 527, righthand winding of, n'iarginal relay 528, conductor 529, lower contact of sequence switch spring 328, upper contact of sequence switch spring 306, conductor 307, terminal 235, brush 236, conductor 237 contact of sequence switch ization of relay 777 com lit) Since only a low spring 23. conductor 239, lower right-hand contact of sequence switch spring 775, lefthand armature and front contact of relay 766, low resistance 782 to grounded battery. resistance is included in this circuit, relays and 528 are both energized and lock up through their left hand windings. At the same time a circuit is completed from grounded battery, winding of relay 530, conductor 531, left-hand contacts of sequence switch spring 325, conductor 322, terminal 250, brush 251, conductor 252, left-hand contact of sequence switch spring 783, left-hand armature and front contact of relay 760 to ground. Relay 530 is energized in this circuit and locks up through its left-hand armature and front contact to grounded conductor 504.

lVhen sequence switch 700 reaches position 11, a circuit is completed from grounded battery, lefthand winding of marginal relay 525, conductor 526, left-hand contact of sequence switch spring 327, left-hand contact of sequence switch spring 313, conductor 314, terminal 246, brush 247, contact of sequence switch spring 248, conductor 249, contact of sequence switch spring 781, outer righthand armature and front contact of relay 766, conductor 793, high and low resistance windings of relay 789 in series, upper armature and back contact of relay 7 94 to ground. Relay 789 is energized in this circuit, but due to the fact that the high resistance lefthand winding of relay 789 was included in this circuit, marginal relay 525 does not be come energized. Relay 789 upon energization locks up through its inner right-hand armature and front contact and in doing so removes the shunt from about the winding of relay 794, which relay therefore becomes energized. The energization of relay 789 completes a circuit from ground, winding of relay 318 (Fig. 3), upper contacts of sequence switch spring 319, conductor 330, right-hand winding of marginal relay 532, conductors 518. 310 and 311, terminal 240, brush 241, conductors 242 and 243, upper left-hand and lower right-hand contacts of sequence switch spring 244, conductor 245, upper left-hand contact of sequence switch spring 774, high resistance 785, conductor 786, outer right-hand armature and frontcontact of relay 789, low resistance 787 to grounded battery. An alternate path is closed at the same time extending from conductor 245 by way of the lower right-hand contact of sequence switch spring 774, lefthand armature and front contact of relay 761 to conductor 786 and thence to grounded battery as described. Resistance 785 is short circuited by this last traced path and therefore relays 532 and 318 are both. energized.

The energization of relay 318 completes a circuit from grounded battery, power mag net of sequence switch 300, armature and back contact of relay 315, upper left-hand and lowerright-hand contacts of sequence switch spring 317, armature'and front contact of relay 318 to ground, to move sequence switch 300 out of position 9 and into position 10. 'When sequence switch 300 leaves position 9, relays 318 and 789 are deenergized, but relay 532 remains energized due to the fact that it has closed a locking circuit through its left-hand winding and lefthand armature and front contact to grounded conductor 504. Y I

The deenergization of relay 789 completes a circuit from grounded battery, power Ina-gnet of sequence switch 700, upper right-hand contact of sequence switch spring 788, righthand armature and back contact of relay 777, lower armature and front contact of relay 794, inner right-hand armature and back contact of relay 789 to ground, for moving this sequence switch out of position 11 and into position 12. As soon as sequence switch 700 leaves position 11, relay 794 is deenergized. At the same time the locking circuits of the various register relays of Fig. 7 are opened at the lower contacts of sequence switch spring 719 and all these relays are restored to their normal condition.

Relays 764, 800, 801 and 757 are used to determine the selection of one ofa number of counting devices. One of these counting devices is operated each time the register relays of Fig. 7 are put into use. The mechanical construction of'these counting devices may be similar to that of a message register. In the present case the counting device connected to lead 802 would be actuated over a circuit extending from grounded battery, through such counting device (not shown), outer right-hand armature and back contact of relay 801 left-hand armature and front contact of relay 757 to ground at the upper left-hand contact of'sequence switch spring 719. This counting operation takes place while the sequence switch 700 is being advanced through positions 9 to 11 inclusive. It is obvious that by operating various combinations of the four relays shown, seven counting devices may be used to record how many of each of seven kinds of calls have been set up on'the registering device.

hen sequence switch 700 reaches position 12, a circuit is completed from grounded battery, power magnet of sequence swltch 200, upper left-hand contact of sequence switch spring 206, conductor 253, contact of sequence switch spring 803 to ground, for moving sequence switch 200 out of position 6 and into position 8. q

WVhen sequence switch 200 reaches position 8, a circuit is completed from grounded battery, power magnet of sequence switch 700, conductor 705,

lower right-hand contact 

